Figure 1.

Human immunodeficiency virus type 1 (HIV-1) AD8-infected macrophages show low levels of cell surface tetherin and high levels of virus release in the absence of Vpu. (A) p24 Gag in cell-free culture supernatants from AD8-infected monocyte-derived macrophages (MDMs) were determined using ELISA; (B) AD8-infected MDMs were stained for cell surface tetherin and intracellular p55/p24 Gag. Asterisks mark infected cells. Single confocal sections are shown. Scale bars = 20 μm; (C) Cell surface tetherin levels of AD8-infected MDMs were analysed by flow cytometry. Uninfected MDMs were immunolabelled with anti-vesicular stomatitis virus glycoprotein (VSVG) as a staining control. The left-hand panel shows the result from a representative experiment; the right-hand panel shows the average relative tetherin mean fluorescence intensities of three donors ± standard error of the mean (SEM). Bars represent the relative means ± SEM of triplicate samples from three donors.